In many parts of Australia, households are entirely reliant on rain water for their household use.
The last may be so because the household is not provided with a mains reticulation supply such as by being too remote from such a supply or because locally available artesian water is not of a quality suitable for household use or perhaps, merely, that the colour or taste is not acceptable to a household.
Where a household is reliant upon rain water, it is usual to collect rain water from roofs of houses, garages, sheds and often every available surface via some collection channelling such as spouting and to deliver the rain water collected to large tanks which may be above ground or below ground or partly above ground and partly below ground.
Such tanks have commonly been made of corrugated galvanised iron but more recently concrete and fibreglass tanks have been used.
Within suburban areas of Australia there is usually a mains reticulation supply of water but to many people the water supplied is not considered to be of particularly high quality.
This consideration of quality may arise out of the fact that most mains reticulation supply deliver water which may have been chlorinated and which may contain other chemicals and further which may contain fluoride which can be unacceptable to many people.
Many suburban houses have a roof area quite sufficient to collect a substantial amount of rain water at least for drinking and washing purposes although probably not also for garden watering purposes but nowadays few people wish to have large tanks on their land having regard to the amount of space that those tanks might take up and also due to the fact that those tanks are usually not visually attractive.
Further, most suburban households would be content with a relatively small tank of rain water to be intended for use only as drinking water or as cooking water and for other water requirements, such as washing and garden water, the household may be quite content to rely upon the mains reticulated supply.
Thus, it is postulated that a suburban household could be quite content with a small rain water vessel for the limited purposes of drinking and cooking.
While it is possible to build a tank of reasonably small size, say 300 liters or less, and it may be possible to locate that tank in a position in which it is not visually obtrusive or objectionable, there are other problems involved of collecting rain water in a suburban environment.
One problem of a small rain water vessel is that it will fill quickly and hence when rain commences it can reasonably be expected that the rain water vessel will be filled within a short time of commencement of rain.
However, various oxidation products collect upon roofs of houses and the atmosphere in a suburban environment is not particularly clean as it contains sulphuric acid, sulphonic acid, nitric acid, hydrogen chloride, nitrous oxide and other pollutants.
Many of those pollutants are washed from the roof and the atmosphere during an initial period of raining and thus rain water in, say, the first five minutes of a rainfall is likely to be substantially polluted and such pollutants will pass into the rain water.
In the context of a large tank, say 3000 liters or above, the amount of pollutants collected in the tank may not be considered to be very significant but in respect of a small tank of say 300 liters or less which will fill quickly, it will be found that the water in the small tank will be relatively more polluted than would be the water in a large tank.
Thus, it is considered that during a period of continuous rain, the initial rainfall will be heavily polluted but the later rainfall will be clean and relatively pure.
This is considered further below.
Water is the simplest chemical compound of importance to living things, the most common molecule in the human body is water, most of the chemical reactions that occur in the body require water, and many properties of water make it essential to life processes.
People want drinking water that is free of bacteria, sparkling clear, and without an objectionable taste or odour. So after water is drawn from a source, it is piped into a treatment plant. The plant may put the water through one or several processes, depending on the quality of the untreated water, and on a city's standards. Many cities use three basic processes: (1) coagulation and settling, (2) filtration, and (3) disinfection. All requiring the addition of various chemicals, mainly the chemical chlorine. The weight of evidence suggests that chlorination by-products pose substantial cancer risks that should be reduced.
Alternatives must provide a similar level of protection, excluding the dependence of chemical additives. Perhaps the most viable alternative is point of use water treatment units.
Applicant has considered a filterised water tank ideally suited for most homes and units of all sizes. Applicants tanks are mostly made from high quality grade 304 stainless steel.
Rainwater tanks have been used for the collection of drinking water for many years by the rural community. In the urban areas, however, water tanks are deemed to be unsuitable because of the presence of airborne contaminants, often lead from exhaust emissions. (It is good news that air lead levels in Australia's major cities have fallen dramatically following the introduction of unleaded petrol in 1985. For example, in Sydney there was a 60% fall in lead in the air over the 12 months to November, 1994, and another significant drop is anticipated following further reductions in the lead content of leaded petrol). Applicant's unique filtration system is hoped to ensure airborne pollutants combined with rainwater, are diverted away into the downpipe.
The problem of roof pollution, is also considered by Applicant's system. The rainwater runs through desirably a stainless steel sieve which reduces leaves, etc., and from there flows into a dump tank. This tank holds 18 liters of the initial rainwater, which may be contaminated. This unclean water slowly filters out into an overflow pipe and then into the downpipe. When the dump tank is full, the remainder of the rainfall gets diverted into the main body of the tank, which stores 230 liters. This is the cleanest water obtainable from the rainfall.
Every rainfall is desired to pass through the filtration system, and the clear water desirably enters and circulates with the stored water. This process hopefully ensures the drinking water remains fresh.
Not every rainfall will help fill the main storage section. On days with only the occasional drizzle, there would not be enough consistent rainfall to keep the dump tank full. However, even this rainfall is beneficial as it helps dispose of roof contaminants, and assists with keeping the guttering clean and ready for the next rainfall.
The World Health Organisation in conjunction with Agriculture and Resource Management Council of Australian and New Zealand, has defined guideline values to represent the level of additives that ensures an aesthetically pleasing drinking water, and does not result in any significant risk to the health of the consumer. In recent years, however, there have been calls by some community groups for water authorities to stop adding certain chemicals to water supplies.
Improvements in water treatment and management have been heralded as the single most important public health initiative ever to be adopted in developed countries. As our population centres grow, increasing demands are being placed on our water resources. Not only is the water itself being placed under stress, but also the systems which collect and deliver it to our taps.
Applicant considers its tanks are a useful solution to the health conscious water consumers, and also to people who live in areas which have particular problems with tap water. It can be used in combination with existing rural water tanks. It is an affordable alternative to tap-water filtration units, and perhaps in the long term, to bottled spring and mineral water.
Some of the chemicals used in water supplies have come under scrutiny, as have treatments like aluminium and additives like fluoride. The debate about whether they should be used has been continuing for years. Those people concerned with chemicals in drinking water can be reassured that their health is not at risk if they consume rainwater for what that reassurance is worth.
Some areas can have dirty water problems due to corrosion of household plumbing pipes and water mains pipelines, or are situated near the end of a water mains pipeline, and have to deal with continual chlorine build up. This problem is non-existent with Applicant's tanks.
The sales of bottled spring water and tap-water filtration units is growing. After the initial purchase of a tank, there are no ongoing costs for replacement parts or water supplies.
A tank offers the suburban residents the option of owning their own private water supply. They are reassured that the water consumed is free of any additives. Tank water does not require in Applicant's view, any chemicals to improve its drinking qualities, the water is soft and refreshing and also beneficial for cooking purposes.
Australian water quality is accepted as one of the best in the world, and yet even here many people choose to improve it by using tap filters, or choose to buy bottled water.
The most frequent concern about drinking water is its bacteriological quality. Stainless steel is Applicant's choice for its hygienic superiority and its corrosion resistance over other materials.
The present invention seeks to provide apparatus which will reject an initial component of a period of rain but accept a later component of that period of rain.